Dendrocephalus (Dendrocephalinus) alachua ( Dexter, 1953 )

Rogers, D. Christopher, Dunn, Ann & Price, W. Wayne, 2019, A review of Dendrocephalus (Dendrocephalinus) (Crustacea: Anostraca) with the first records of male-male anostracan aggressive competition, European Journal of Taxonomy 509, pp. 1-14 : 5

Dendrocephalus (Dendrocephalinus) alachua ( Dexter, 1953)

Fig. 1B, E

Branchinella alachua Dexter, 1953: 761 , figs 24–28.

Branchinella alachua – Moore 1967: 219 –220. — Belk & Sissom, 1992: 314. — Belk & Brtek 1995: 323. — Brendonck 1997: 451 –454. — Brtek 1997: 21. — Brtek 2002: 54. Dendrocephalus alachua – Rogers 2006: 7, 12.

Material examined

Holotype

USA • ♂; Florida, Alachua County; 6 Jul. 1947; R.W. Dexter leg.; USNM 93538 .

Paratypes

USA • 3 ♂♂; same data as for holotype; USNM 93539 .

Other material

USA • 5 ♀♀, 7 ♂♂, plus 26 ♀♀, 33 ♂♂ reared in culture; Hillsborough County, Tampa, Cemetery Pond , corner of Martin Luther King Boulevard and East Lake Avenue ; 27°58.859΄ N, 82°24.256΄ W; 13 Sep. 2000; substrate collected for culture 6 Jul. 2000; W.W. Price leg.; DCR # 772 • 41 ♀♀, 6 ♂♂; David E. West Park, 2212 East 97 th Street, corner of Martin Luther King Boulevard and East Lake Avenue ; 28°02.270΄ N, 82°26.063΄ W; 8 Jan. 2008; W.W. Price leg.; DCR #774 .

Remarks

The original description of the female has the brood pouch elongate, almost fusiform. In many, but not all, female specimens I have cultured, the brood pouch is abbreviated, lacking the free distal portion ( Fig. 3E ). This species is known from five unspecified collections in Alachua County, Florida, near Gainesville ( Dexter 1953; Moore 1967; two unpublished records at USNM), and was suggested as possibly extinct, pending further surveys, even after many surveys were performed ( Rogers, 2006). However, collecting efforts by W.W. Price yielded two new localities in the Tampa region. The Tampa locality is at least 180 km south of the unspecified type locality (a “barrow pit” ( Dexter 1953) which has probably been destroyed (Rogers 2006)). For both new locations for this species the substrate has no measurable calcium carbonate and salinity 0 to ~2 mS/cm, as both locations are heavily vegetated, and have tree cover, with the substrate covered in vegetative debris ( Rogers 2014b; this study). Similarly, both locations are less than a meter above the water table.

Dendrocephalus alachua co-occurred at both new locations with the smooth clam shrimp Lynceus gracilicornis Packard, 1871 , and the spiny clam shrimp Eulimnadia cylindrova Belk, 1989 . Both Dexter (1953) and Moore (1967) reported D. alachua co-occurring with the anostracan Streptocephalus sealii Ryder, 1879 . However, this species was not present at either of the two new localities.

Rogers (2006) conservatively designated D. alachua as CR A1 species (IUCN 2000) pending further surveys. But with these new collections this species meets the IUCN red list CR B1a,b species criteria (IUCN 2000), that the species is ‘Critically Endangered’, with an extent of occupancy less than 100 km 2, and a projected decline in extent of occurrence.

Figures

Fig. 1. Dendrocephalus spec. A. Dendrocephalus acacioidea, male head, left side, anterior view. B. Dendrocephalus alachua, male head, left side, anterior view. C. Dendrocephalus lithacus, male head, left side, anterior view. D. Dendrocephalus acacioidea, brood pouch, right, lateral view. E. Dendrocephalus alachua, brood pouch, right, lateral view. F. Dendrocephalus lithacus, brood pouch, right, lateral view. G. Dendrocephalus lithacus, male, labrum, ventral view. H. Dendrocephalus lithacus, gonopods, right, lateral view. Scale bar: A–C = 1 mm; D–F, H = 4 mm; G = 0.25 mm.

Fig. 3. Dendrocephalus proeliator sp. nov, male-male aggressive interactions. A. Encounter. B. Circling. C. Head to head attack. D. Broadside attack. E–F. Chasing.